Efficacy and Safety of Guanfacine Extended-Release in the Treatment of Attention-Deficit/Hyperactivity Disorder in Adults: Results of a Randomized, Double-Blind, Placebo-Controlled Study.
Iwanami A, Saito K, Fujiwara M, Okutsu D, Ichikawa H.
J Clin Psychiatry. 2020 Apr 14;81(3). pii: 19m12979.
Commentary* by Dr. Margaret Weiss: It would appear that the profile of response in adults is not unlike that in children. In adults, decrease in blood pressure may be an advantage for some patients.
OBJECTIVE: To assess guanfacine extended-release (GXR) efficacy and safety in adults with attention-deficit/hyperactivity disorder (ADHD).
METHODS: This phase 3, double-blind, placebo-controlled study (conducted between October 2016 and July 2017) included Japanese patients aged ≥ 18 years with ADHD (DSM-5). Patients received GXR (n = 101) or placebo (n = 100) titrated from 2 mg/d to 4-6 mg/d (dose-optimization; 5 weeks), followed by 4-6 mg/d (dose-maintenance; 5 weeks), then tapered doses to 2 mg/d (2 weeks). Primary endpoint was change from baseline in total score on the Japanese version of the ADHD-Rating Scale IV with adult prompts (ADHD-RS-IV) at week 10. Other measures were ADHD-RS-IV subscales, Clinical Global Impression-Improvement scale (CGI-I) and Patient Global Impression-Improvement scale (PGI-I) (percentage of patients very much improved/much improved), treatment-emergent adverse event (TEAE) incidences, and TEAEs leading to discontinuation.
RESULTS: Compared with placebo, there was statistically significantly greater improvement in ADHD-RS-IV total score reduction with GXR (least squares mean ± SE: GXR vs placebo, -11.55 ± 1.10 vs -7.27 ± 1.07; P = .0005; effect size 0.52). There were significantly greater improvements in GXR for ADHD-RS-IV inattention (-7.39 ± 0.79 vs -4.89 ± 0.76; P = .0032) and hyperactivity-impulsivity (-3.84 ± 0.54 vs -2.10 ± 0.52; P = .0021) subscale scores, CGI-I scores (48.1% vs 22.6%; P = .0007), and PGI-I scores (25.3% vs 11.8%; P = .0283). More patients in the GXR versus the placebo group reported TEAEs (81.2% vs 62.0%) and discontinued due to TEAEs (19.8% vs 3.0%). The main TEAEs in the GXR group were somnolence, thirst, blood pressure decrease, nasopharyngitis, postural dizziness, and constipation; most TEAEs were mild to moderate in severity.
CONCLUSIONS: In Japanese adults with ADHD, GXR improved ADHD symptoms without any major safety concerns.
* Abstracts are selected for their clinical relevance by Dr. Margaret Weiss, Director of Clinical Research, Child Psychiatry, Cambridge Health Alliance, Harvard University. Her commentary reflects her own opinion. It is not approved or necessarily representative of the CADDRA board.